1. Field of the Invention
The present invention relates to an interdental brush, particularly to an anti-loose interdental brush.
2. Description of the Related Art
Referring to FIG. 1, the conventional interdental brush 1 mainly comprises a bristle stem 11, a plurality of bristles 12, and a handle 13. The bristle stem 11 is formed by a plurality of interlaced wires. The bristles 12 are wound and clamped by the bristle stem 11 for orientating. The handle 13 is directly formed by plastic material and covers the bristle stem 11. While using, a user holds the handle 13 and stretches the interdental brush 1 into the mouth (not shown), so that the bristles 12 start to clean the tooth slits. However, the bristle stem 11 covered by the plastic handle 13 only attains the simple engagement. Therefore, the bristle stem 11 is easily loosened, while the user moves or rotates the interdental brush 1 in using. Moreover, the disengaged bristle stem 11 is easy to be swallowed and dangerous for the user. Hence, the interdental brush 1 should be improved.
In order to solve the aforementioned lack of engaging, a Taiwan patent number M314550, entitled “An anti-loose interdental brush”, discloses a bristle stem punched to form a fixing portion. Because the property of an outer diameter of the fixing portion is larger than an outer diameter of the bristle stem, the bristle stem can be firmly engaged in the handle. A Taiwan patent number I3747024 entitled “A method for making interdental brush”, discloses a bristle stem punched to form a plurality of expanding portions with an outer diameter larger than a diameter of the bristle stem. Further, the outermost diameter of the expanding portions is larger than the diameter of a through hole of a handle. Although the aforementioned prior arts attain the engaging and fixing effect of the bristle stem and the handle, there is still a need to be improved after many times of practical tests.